A fuel cell is an electrochemical device that includes two electrodes at opposite surfaces of an electrolyte membrane. In one form, an ion-conducting polymer electrolyte membrane is disposed between two electrode layers. The electrode layers typically include gas diffusion media or gas diffusion layers (GDL). The catalyst coated membrane is often referred to as CCM. The CCM coupled with the GDL is often referred to as a membrane electrode assembly (MEA). The MEA is used to promote a desired electrochemical reaction from two reactants. One reactant, oxygen or air, passes over one electrode while hydrogen, the other reactant, passes over the other electrode. The oxygen and hydrogen combine to produce water, and in the process generate electricity and heat.
An individual cell within a fuel cell assembly includes an MEA placed between a pair of separator plates (also sometimes called flow field plates). The separator plates are typically fluid impermeable and electrically conductive. Fluid flow passages are typically formed in each plate surface and face the electrode layer to facilitate access of the reactants to the catalyzed active area of the electrodes. The flow passages also facilitate the removal of the products of the chemical reaction.
In such fuel cells, resilient gaskets or seals are typically provided between the faces of the MEA and the perimeter of each separator plate to prevent leakage of the fluid reactant and product streams. Since the fuel cell operates with oxygen and hydrogen, it is important to provide a seal that retains hydrogen, oxygen and water.
Thus, it is desirable to have a seal in a fuel cell that facilitates ease of assembly and alignment during an assembly operation while assuring the proper sealing for the finished assembly.